The invention relates, on the one hand, to a method for transmitting a color extraction, defining positions of pixels of a print color to be deposited on a print sheet in a print run, from a prepress system to a press system in order to produce a print product, and on the other hand, to a management information system for integrated planning and control of the production of print products in a networked graphic production, wherein a prepress system and a press system can be connected to the management information system.
Such management information system (MIS) for graphic production, which can also be networked over several locations, is provided by the applicant under the product name “HIFLEX” (www.hiflex.de). The known MIS in a networked print shop, besides facilitating a central control and monitoring of the connected executions systems, e.g. prepress-, press-, and postpress processing systems and warehouse- and distribution systems, also facilitates central date- and execution planning for all occurring print jobs, including job quote generation, based on the parameters of these plans, and accounting, statistics, and quality control, based on the data of the actual execution, in the context of the production of print products.
In print shops, which use the known MIS, furthermore, a method as described above is generally known. According to the rules developed by the consortium “International Cooperation for the Integration of Processes in Prepress, Press and Postpress” (“CIP4-Consortium”, www.cip4.org), or previously developed by the predecessor organization, the prepress system generates a so-called “color extraction” in the context of the production of a print product for each print sheet in print colors, e.g. in the basic colors cyan, magenta, yellow, and black. Said color extraction defines the positions of those image pixels on the print sheet in a bit map file, onto which the respective print color is to be printed.
CIP3 and CIP4 specify the transmission of color extracts with a resolution, which is reduced compared to the print, respectively for the offset print. Such color extractions allow next to the determination of the required “color profiles”, in particular the computation of reduced preview images (so-called “previews”), based on which the operating personnel obtains a coarse optical impression of the respective print run at the print system, and can thus monitor, if the respective print plate belongs to the job to be currently processed, and if the color extraction matches its job.
Color extractions with all image pixels required for the print in the respective print color are transmitted from prepress in particular to digital printers and color lasers, and to offset print systems with an integrated exposure device in the “Tagged Image File Format” (TIFF), developed already in the 90's for color separation with 1 bit color depth (“black and white”).
A color profile for offset printing includes a diagram of the ink requirement, when printing the respective print color on the respective print sheet, plotted over the longitudinal direction of the print cylinder, when passing through the press: the ink requirement over the width of the print sheet is high, when many pixels in the respective color are to be printed in a column extending in circumferential direction of the print cylinder, it is low when only few pixels are to be printed. During printing, the print cylinder, or the print plate is loaded in the press with variable amounts of print ink according to the color profile, along the longitudinal direction of the print cylinder by means of a slide control.
The CIP4 concepts are based on the object to standardize communications between print shop, designer, advertising agency, customer for print products, and subcontractors of contractors in the context of a networked graphic production for all production possibilities and eventualities in a flexible manner and without restrictions. The “job definition format” (JDF), defined for this purpose, and the “job messaging format” (JMF), as a subset of JDF, is based on the “extensible markup language” (XML) of a also generally known META language, developed by the “World Wide Web Consortium” (W3C, www.w3.org) for defining document types, and shall be used as a standard data format for describing processes and products, according to the intention of the CIP4-consortium, not only in all production areas of a network print shop, in particular in sales, job costing, order processing, production planning and control, in production itself, prepress, press, postpress and shipping, in the cross sectional areas, materials-, and warehouse management, financial and payroll accounting, controlling, cost accounting, and quality assurance.
Through vertical integration of data, on the one hand of the production process, and on the other hand, of the accounting sectors, JDF shall facilitate a standardized documentation of the relevant target- and actual data, and seamless production control. In particular, a JDF job shall only be described once in one form, which all process participants understand, also in external communications with customers and subcontractors and their executing systems in the man-machine and machine-machine communication over all language- and platform boundaries.
According to the “JDF specification 1.2” (www.cip4.org), a management information system (MIS) as a functional component of the JDF workflow in a networked graphic production shall monitor processes and communication between system components and system control in the context of this workflow. A press system (“press controller”) controls print equipment and its communication amongst each other, and also with other components. A prepress system (“pre-press workflow system”) provides information from prepress to the press system, in particular from layout, reproduction, and print plate production, including page- and sheet mounting. On the one hand, specially provided hardware systems (in particular also provided by software), on the other hand, also the respective software for these systems is designated respectively as MIS, prepress- and press systems in the context of the known implementations in networked print shops.
A specification for interoperability of the prepress- and press systems (“pre-press to conventional printing ICS” version 1.0, www.cip4.org, Jan. 20, 2005) defines the method, provided according to the CIP4 concepts, for transmitting the color extractions from the prepress system to the press system: the color extractions are initially stored by the prepress system in “portable network graphics” file format (PNG specified according to ISO/IEC 15948:2003), e.g. together with an XML file referencing it, together with additional management information in an area provided for this purpose. The pre-press system then informs e.g. the press system that the color extractions have been stored, and the press system independently retrieves the information, where the color extractions are stored.
Contrary to the philosophy of the CIP4-Consortium, and the concepts of JDF based thereupon, there are multiple restrictions in real life operations of networked print shops, and there are specific differences with respect to the information, which the particular process participants need, or actually use. Information which is useful, or even necessary for one process partner, can be redundant for other process partners or can even be detrimental for useful operations.
For example, execution systems in different stages of development are often used in the same business. Besides equipment, which supports the CIP4-standard, these are still in particular prepress and press systems, which can provide or read color extracts only in “CIP3 print production format” (PPF, a text format, which receives bit maps in the form of MIME coded binary data). The integration of such older systems into a networked print shop impedes or denies the implementation of a complete CIP4-workflow.
In the context of known implementations of CIP workflow in networked graphic productions in the triangular relationship between MIS, prepress-, and press system, color extractions are directly transmitted from the prepress- to the press system, thus not over MIS.
Furthermore, the known CIP4-workflows do not offer a continuously implemented possibility to interfere in a controlling manner, and where necessary in a correcting manner, with the communication between prepress- and press system. Furthermore, in the course of the processing of a print job in prepress, e.g. the number or the systematic allocation of the print plates to be produced (typically due to customer specifications changed at short notice) can change.
In particular, through such changes in the course of the processing of a job, when already before JDF data have been transmitted to the press system, but also generally through different machine specific restrictions with respect to the form and content of communicated data through different data sources and different data volume, e.g. through different color designations in MIS, and on the side of the customer in the pre-press system, the consistency of the job data can be impaired. Also in this case, the allocation of the color extractions to the print runs on the press system requires considerable and error prone manual interference.
It is the object of the invention to provide a method for transmitting color extractions, allowing a coherent management also of the communication between press- and prepress systems in the context of a CIP4 workflow.